December 2011. Human Population Growth: Historical Perspective The human population has experienced exponential growth over the past 200 years. Why? Expanded.

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Presentation on theme: "December 2011. Human Population Growth: Historical Perspective The human population has experienced exponential growth over the past 200 years. Why? Expanded."— Presentation transcript:

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December 2011

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Human Population Growth: Historical Perspective The human population has experienced exponential growth over the past 200 years. Why? Expanded into diverse habitats and climate zones. Development of modern agriculture Modern sanitation and public health advances Development of antibiotics and vaccinations Harnessed concentrated sources of energy

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The Bottom Line No population can continue to grow indefinitely. Degradation of natural systems and resources jeopardizes our ability to sustain populations and build economies. Differential effect of developed vs. developing countries In 2006, developed countries added 1.2 million people Developing countries added 79.5 million people.

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Population Growth Projections By 2050, human population is projected to be between 7.2 and 10.6 billion people. 97% of the growth in developing countries.

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Factors Affecting Human Population Size When births plus immigration exceed deaths plus emigration, population increases; when the reverse is true, population declines. This is true of other species as well as humans.

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Comparison of birth rates and death rates Demographers use: Birth rate or crude birth rate: number of live births per 1,000 people in a population in a given year ( U.S. – 14.18) Death rate or crude death rate: number of deaths per 1,000 people in a population in a given year ( U.S. – 8.27)

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Declining Population: Observing Fertility Rates Fertility – number of children born to a woman during her lifetime. replacement –level fertility - number of children a couple must bear to replace themselves Typically between 2.1 and 2.5 children per couple Total fertility (TFR) – average number of children a woman typically has during her reproductive years Global average about 2.7 Developed countries about 1.6 United States – 2.06 Developing countries about 2.9 Range according to CIA (0.91 in Macau and 7.68 in Niger)

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Population Projections

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Case Study: Fertility and Birth Rates in the U.S.

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1900 – 76 million Americans Baby boom – post WWII – 1946 to 1964 Birth rate up to 3.7 at one point Corresponding “baby bust” – 1964 to 1977 Due to delayed marriage, contraceptive use, and abortion 2007 – saw 300 millionth American 56% growth due to birth rate, 44% due to immigration Immigration shift from Europe to Latin American/Southeast Asia High per capita resource use Case Study: Fertility and Birth Rates in the U.S.

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Think about how life has changed… Case Study: Fertility and Birth Rates in the U.S. In the United States in 1905… Three leading causes of death: pneumonia, tuberculosis, and diarrhea 90% of doctors had no college education 1 out 5 adults cannot read or write Average U.S. worker earns $200-$400 per year Only 9,000 cars in the U.S. with 144 miles of paved roads 3 minute phone call cost $11 30 people live in Las Vegas, NV Most women washed their hair once a month In the United States NOW… Three leading causes of death: heart disease, cancer, stroke Common path to becoming a physician requires 8 years of college and 3-8 years of internship and residency 99% literate Average U.S. worker earns $42,028 per year (2005 figures according to Worldsalaries.com) 450 million cars in the U.S. with 5.7 million miles of paved roads 3 minute phone call costs $0.51 (according to Mr. Bromwell’s cell phone plan) 567,641people live in Las Vegas, NV I would imagine hair washing is daily among other things… Tractor-plow, 1905

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Factors Affecting Birth Rates and Fertility Rates Importance of children as part of the labor force Cost of raising and educating children Availability of private and public pension systems Urbanization Educational and employment opportunities available for women Infant mortality rate Average age at marriage (or first child) Availability of legal abortions Availability of reliable birth control methods Religious beliefs, traditions and cultural norms

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Life Expectancy and Infant Mortality Rate Two useful indicators of overall health of a population: Life expectancy – average number of years a newborn infant can expect to live Infant mortality rate – number of babies out of every 1,000 born who die before their first birthday Single best measure of a society’s quality Reflects overall nutrition and health care

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Infant Mortality in the U.S. In U.S. approximately 6.3 deaths / 1,000 births Higher than expected due to inadequate health care for poor women during pregnancy, drug addiction among pregnant women, and a high birth rate among teenagers.

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Population Age Structure The distribution of males and females in each age group in the world’s population Age structure diagrams  Examine # of people in three age categories prereproductive reproductive postreproductive

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Population Age Structure Diagrams

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The Baby-Boomers This generation makes up half of all adult workers and dominates demand for goods and services.

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Consequences of Population Decline Can threaten economic growth Less government revenues with fewer workers Reduces availability of young people for military service Less entrepreneurship and new business formation Less likelihood for new technology development Increasing public deficits to fund higher pension and healthcare costs

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Global Aging

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The Demographic Transition

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Fig. 9-15, p. 186 Total fertility rate Percentage of world population Population Population (2050) (estimated) Illiteracy (% of adults) Population under age 15 (%) Population growth rate (%) 17% 20% 1.1 billion 1.3 billion 1.6 billion India China GDP PPP per capita Percentage living below $2 per day Life expectancy 47% 17% 36% 20% 1.6% 0.6% 1.4 billion $5,890 $3, years 62 years children per women (down from 5.7 in 1972) Infant mortality rate 2.9 children per women (down from 5.3 in 1970)